Nannotax3 - ntax_mesozoic - Grantarhabdus

Grantarhabdus


Classification: ntax_mesozoic -> Podorhabdales -> Cretarhabdaceae -> Grantarhabdus
Sister taxa: Mattiolia, Wisea ⟩⟨ Speetonia ⟩⟨ Cruciellipsis, Flabellites, Grantarhabdus, Helenea ⟩⟨ Cretarhabdus, Retecapsa, Pickelhaube, Miravetesina

Distinguishing features:
Parent taxon (Cretarhabdaceae): Regular placoliths; central-area spanned by elevated distal structure typically with cross bars and central spine.
The distal shield usually weakly bicyclic, with narrow outer-cycle and broad inner-cycle; elements usually radial and non-imbricate. LM image is moderately birefringent. V/R structure unclear.
This taxon: Cretarhabdids with relatively narrow shields; central area wide with diagonal cross bars.


Daughter taxa (time control age-window is: 0-800Ma)
Grantarhabdus camaratus
Large (ca 8-10 µm) cretarhabdid with diagonal cross and space in between crossbars filled by perforate net.
Grantarhabdus coronadventis
Medium to large( 6-12 µm) cretarhabdid with diagonal cross.
Grantarhabdus meddii
Medium to large( 7-10 µm) cretarhabdid; central area wide with diagonal cross - crossbars at low angle and meet to form a solid bar for about half their length.
Grantarhabdus sp.
Specimens not identified to species level

Taxonomy:

Citation: Grantarhabdus Black, 1971
Rank: Genus
Type species: Grantarhabdus meddii Black, 1971
Synonyms: Gephyrorhabdus Hill, 1976 (type species G. coronadventis)

Farinacci & Howe catalog pages: Grantarhabdus + * , Gephyrorhabdus *

Distinguishing features:
Parent taxon (Cretarhabdaceae): Regular placoliths; central-area spanned by elevated distal structure typically with cross bars and central spine.
The distal shield usually weakly bicyclic, with narrow outer-cycle and broad inner-cycle; elements usually radial and non-imbricate. LM image is moderately birefringent. V/R structure unclear.
This taxon: Cretarhabdids with relatively narrow shields; central area wide with diagonal cross bars.

Search data:
TagsLITHS: placolith, elliptical, CA: ca_disjunct, process, diagonal cross, CROSS-POLARS: rim-unicyclic, R-prominent,
MetricsLith size: 0->0µm;
Data source notes: size range of included species
The morphological data given here can be used on the advanced search page. See also these notes

Geological Range:
Last occurrence (top): at top of Campanian Stage (100% up, 72.1Ma, in Campanian stage). Data source: Total of range of species in this database
First occurrence (base): at base of Berriasian Stage (0% up, 145Ma, in Berriasian stage). Data source: Total of range of species in this database

Plot of occurrence data:

References:

Black, M. (1971a). Coccoliths of the Speeton Clay and Sutterby Marl. Proceedings of the Yorkshire Geological Society. 38: 381-424. gs

Bown, P. R., Rutledge, D. C., Crux, J. A. & Gallagher, L. T. (1998). Early Cretaceous. In, Bown, P. R. (ed.) Calcareous Nannofossil Biostratigraphy. British Micropalaeontological Society Publication Series. 86-131. gs

Hill, M. E. (1976). Lower Cretaceous calcareous nannofossils from Texas and Oklahoma. Palaeontographica Abteilung B Palaeophytologie. 156: 103-179. gs

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Grantarhabdus compiled by Jeremy R. Young, Paul R. Bown, Jacqueline A. Lees viewed: 16-1-2022

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